Mechanical hand



T. C. HARRY MECHANICAL HAND May 26, 1953' 4 Sheets-Sheet l Filed D90. l,1947 NM hm.

ZZ Cjaff/z INVENTOR ATTORNEYS T. C. HARRY MECHANICAL HAND l May 26, 19534 Sheets-Sheet 2 Filed Dec. l, 1947 T. @Harig Dn m m ATTORNEYS.

May 26, 1953 T. c. HARRY MECHANICAL HAND 4 Sheets-Sheet 3 Filed Dec. l,1947 ATTORNEYS May 26, 1953 1'.. c. HARRY 2,639,437

MECHANICAL HAND Filed Dec. 1, 1947 4 sheen-sheet 4 INVENTOR ATTORNEYS vPatented May 26, 1953 UNITED STATES PATENT OFFICE 2,639,437 MECHANICALHAND Thomas C. Harry, Ferndale, Mich.

Application December 1, 1947, Serial No. 789,098 12 claims. (o1. 3-12.6)

This invention relates to improvements in articial or mechanical hands.

An object of the invention is to provide an improved artiiicial ormechanical hand and forearm construction which will be secured in anydesired manner to the stump of an amputee.

Another object of the invention is to provide an improved constructionof artificial or mechanical hand and forearm, which will be securelystrapped to the stump of an amputee, said hand being hydrauliciallyoperated by pumping the forearm up and down to build up pressurev uponthe hydraulic fluid to force the same from a storage tank contained inthe forearm past a control valve and into a small cylinder to operate apiston and the ngers and thumb of the hand operatively connected withsaid piston.

A further object of the invention is to provide an improved artificialor mechanical hand and forearm construction which will be securelystrapped to the stump of an amputee, said hand being hydraulicallyoperated by pumping the forearm up and down to build up pressure uponthe hydraulic fluid contained in a storage tank in the forearm, wherebythe fluid will be forced into a small control cylinder to operate apiston slidably mounted therein, which in turn will operate theinterconnected fingers and thumb of the mechanical hand, said fluidunderl pressure being released by the operation of a control valveassociated therewith to permit a compressed spring to force the pistonto its original position and the hydraulic uid back into the storagetank.

A still further object of the invention is to provide an` improvedconstruction of hydraulically operated artificial or mechanical hand andforearm which may be held at any desired angle, and the ngers and thumbof the hand operated as desired.

Another object of the invention is to provide an improved hydraulicallyoperable artificial or mechanical hand and forearm which will be highlyeicient in operation and relatively inexpensive to manufacture andproduce.

Other objects will appear as the description proceeds. v

In the accompanying drawings which form a part of this application,

Figure 1 is a side elevational view of the improved artificial ormechanical hydraulically opera-ted hand and forearm construction;

Fig. 2 is a partial vertical sectional view through the improvedartificial or mechanical hand and the adjacent portion of the. forearmconnected therewith;

Fig. 3 is a plan'view of the improved artiiicial hand and the adjacentportion of the forearm.

v with portions thereof being broken away and in section to show theoperating mechanism for the fingers and thumb of the hand;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 1;

Fig. 5 is an enlarged side elevation of the articial or mechanicalforearm, with parts thereof being broken away and in section to moreclearly show the ratchet operating mechanism for actuating the pistonfor controlling the hydraulic fluid used for operating the fingers andthumb of the hand;

Fig. 6 is an end elevation of the elbow end of the forearm portion ofthe artificial or mechanical hand, showing the attaching pad thereforattached to an arm stump;

Fig. 7 is a sectional view taken on the line I-l of Fig. 4, with aportion thereof being broken away to show the control valve, and

Figure 8 is a sectional view taken on the line 8-8 of Fig. 1.

Like characters of reference are used throughout the followingspecification and the accompanying drawings to designate correspondingparts.

In carrying out the invention, there is provided an improvedconstruction of artiiicial or meohanical hand and forearm which willinclude a hollow cylindrical forearm portion I which may be cast from alight weight material such as aluminum, and the forward or outer endthereof will be slightly tapered as at 2.

A hand portion 3 of hollow construction is also cast from aluminum, andis formed at its inner end with a cylindrical bearing sleeve 4 and whichis formed with an annular locking groove or slot 5 which cooperates witha similarly formed cylindrical Wrist forming bearing sleeve 6 alsoformed with an annular locking groove 'I and having a reduced inner end8 which is externally threaded at 8' to screw into the internallythreaded bore I0 in the outer end of the tapered front end 2 of theforearm portion I.

A split connecting clamp II having spaced internally disposed ribs I2and I3 is adapted to be positioned about the sleeves 4 and 5 with theribs I2 and I3 being received in the annular locking .slots or grooves 5and V1. Securing screws I4 and I 5 are disposed in parallel bores I6 andI1 formed in one portion of the split clamp II and are threadable inthreaded bores I8 and I9 in the other portion of the clamp II` whendisposed about the sleeves 4 and 6 for locking the hand portion 3 to thewrist forming bearing sleeve 6 supported by the forearm portion 2.

The-internal bore 20 formed in the hollow forearm portion I isinternally threaded at 2| to support the externally threaded lockingring 22 which holds the closed inner end 23 of the large cylinder 24 inposition within the inner end of said bore 20. An inwardly extendingexternally threaded sleeve or bushing 25 is formed integrally with andcentrally of the closed end 23 of the cylinder 24, and connected with acentral opening 26 formed through said closed end 23. A packing nut 21is internally threaded for screwing upon the threaded sleeve or bushing25, and provides a backing for the piston rod 28 which is reciprocablymounted through the packing and supports a piston 29 on its forward endfor operation in the cylinder 24.

An annular hydraulic fluid containing tank 38 will be supported withinthe bore 20 in the forearm portion I, and will be provided with anoppositely disposed outlet port 3| and return port 32 which connectrespectively with the fluid passages 33 and 34 formed in the wall of theforearm portion I.

A coil spring A35 will be disposed about the piston rod 28 between thepacking nut 21 and the sleeve 36 secured about the piston rod 28 bymeans of the cross pin 31.

A larger and heavier coil spring 38 will be disposed about the inner endof the piston rod 28 between the sleeve 36 and the sleeve 39 secured tothe inner end of said piston rod 28 and the oppositely extendingtrunnions 48 and 4| upon which the arms 42 and 43 of the pistonoperating yoke 44v are mounted.

The yoke 44 is secured to a cross shaft 45 xed transversely of the innerend of the forearm portion I by means of the pins 46,-whereby the yoke44 will rock back and forth to reciprocate the piston 29 in the cylinder24.

A ratchet wheel 41 willbe fixed to the cross shaft 45 at one end of theyoke 44, and will be formed with a pluralityof teeth 48.

A transversely extending pivot shaft `49 will be ydisposed horizontallyacross'the center of the inner end of the forearm portion and will serveas an elbow pivot joint. A stump vengaging cup 50 will be formed withthe spaced depending arms I and y52, which will be piv otally supportedat their lower ends upon the pivot or elbow joint shaft 49. The cup 56may be attached to the stump 53 of the amputee by means of straps (notshown) or in any other desired manner.

An offset operating lever 54 will be pivoted at its upper end upon a'pin 55 operating in the elongated opening 55', the pin being supportedby the arm 5| with its lower end formed intoa bearing 56 disposed aboutthe shaft-45.

An inwardly extending supporting post 51 will be supported from theinner surface of the forearm and will pivotally support the Atrip arm 58having a yoke 58 -on its inner end which supports a pin 80 upon whichthe'arm 6| is pivotally mounted. The arm 6| is formed with the yokes 62and 63 at its opposite ends, said yoke 62 supporting a cross pin 64 uponwhich the pawl or dog 65 is-also mounted. The pawl or dog 65 is alsopivotally mounted upon the pin 66 supported by the operating lever 54.

A second pawl or dog 61 is pivotally mounted on the cross pin 68supported by the yoke 63, and is further pivoted upon the pin B9 securedto the forearm portion I. It will be understood that the pawls'or dogs65 and 61 engage the teeth 48 on the ratchet wheel 41 when the trip arm58 is moved to its upper-position, and the 4 pawls or dogs 65 and 61will be released from the ratchet wheel 41 when the trip arm 53 is in alowered position.

Extending rearwardly from the inner end of the forearm portion I andpivoted upon a pin 10, is a rack bar 1| having teeth I2 upon the upperedge. The rack bar is slidably supported adjacent its rear end in abracket member 13 secured to the inner surface of the depending arm 52supported by the cup 58. An operating shaft 14 is rotatably disposedthrough the depending arm 52 and supports a pawl or dog 'I5 on its innerend engageable with the teeth 'I2 on the rack bar 1|, and an operatinghandle 16 on its outer end, the function of the rack bar 1| and pawl ordog 'I5 being to support the forearm portion I in the desired angularrelation with respect to the cup 5U attached to the stump 53. v

A valve seat 11 isformed at the forwardend of the fluid passage 34 andcooperates with a ball check valve l'l. A screw closure 19 is providedfor gaining access to the ball check valve 18. A port is formed throughthe cylinder 24 and is adapted to register with the valve seat 11.

An outlet port 8| isformed through the forward end or closure 82 of theforearm portion I, and is adapted to cooperate with a control valve 83reciprocably mounted in a transverse boref84 formed through theforearmportion i. An annular groove 85 is formed about the valve 83 andis adapted to register with the outlet port 8| when the Valve 83 ismoved inwardly against the compression of the coil spring 86 reclined inthe inner end of the bore 84. An i.- shape outlet passage 81 is formedin the inner end of the valve 33, and when the valve is in its outerposition, connects Athe return passage 33 in the forearm-portion Iwiththe passage 88 formed inthe forearm portion l, diametricallyopposite the bore orpassage 8|.

A small cylinder .89 is received in a small bore 90 formed axially inthe tapered portion 2 of the forearmportion I, and cooperates with apiston 9| having a forwardly extending piston rod 92, forked at 93 atits outer end, and extending through the bore 94 in the closed outerendV 95. A threaded packingnut 96 is threaded upon the forwardreducedend 91 of the cylinder 89. A coil spring 90 is disposed aboutthepiston rod 92 within the cylinder 89, and extends the full Vdistancebetween the piston9| and closed outer end of the'cylinder 89.

The tapered portion 2 of the forearm I is longitudinally slotted toreceive the valve actuating lever 98 pivoted at 99 in the outer end ofthe slot and having its opposite end pivotally attached'by the pin |88to the outer end of the valve 83. .A cam lill is formed on the lever 98and is engageable by the valve actuating finger or control piece |82pivotally mounted upon the pin |83 between the ears |04 on the taperedportion 2. In the position shown in Fig. 4 the valve is in position topermit the hydraulic fluid to pass from the cylinder 89 through thepassages 88 and 81, and through the passagek 33' back into the fluidsupply tank 38. Obviously when the finger piece is moved in the oppositedirection the port or passage 8| lwill be aligned with the annulargroove 85 and the passage 88 to permit the hydraulic iuid from thecylinder 24 to be pumped into the cylinder 89 as the forearm portion Iis moved up and down, thus actuating the ratchet mechanism armiadvancingthe largepiston 29 in the cylinder 24, thereby building' up thepressure on the hydraulic fluid in the small cylinder 89. Y

Secured between the forked ends 93 of the piston rod 92 is an ear |05held by a pin |06 and connected to a transversely extending bar |01which supports the four spaced forwardly eX- tending finger operatingrods |08, which have reduced outer extremities |09 for Abeingtelescopically received in the bores in the tubular connecting membersCoil springs ||2 are disposed in the hollow connecting members ||I atthe forward ends of the reduced extremities |09 of the finger operatingrods |08, and pins ||3 are supported by each of said extremities |08 andextend upwardly through slots ||4 formed in the inner ends of each ofsaid connecting members I I I.

The outer ends of the connectingmembers I are slotted at ||5 to receivethe ears |I6 on the .inner ends of the fingers forming plates i1, and

lower ears I|8 are also formed on the plates ||1, the same being slottedat ||9 to receive the cross pins |20. The outer ends of the plates ||1are formed with a toothed segment |2| engageable or meshable with a liketoothed segment |22 on the finger tip plates |23. Spaced connectingplates |24 and |25 are disposed on the opposite sides of the toothedsegments |2| and |22 and are secured in position by the pins |26 and |21extending therethrough and through the plates |23 and ||1. Finger tipcontrol links |28 are pivoted at their inner ends on the rivets |29supported by the hand portion 3, and are also pivoted at their outerends on the pins |30 supported by the connecting plates |25, If desireda fiexible cover |3| colored to simulate flesh color may be disposedabout the several fingers and thumb |32, hereinafter described.

A thumb |32 will be pivotally supported upon a threaded screw |33secured to the hand 3, and will also support the interconnected togglelinks 34 and |35, mounted respectively upon the pins |36 and |31. Athumb control lever |38 will be forked at its outer end and connected bymeans of the pins |39 with the toggle link |35 The lever |38 will extendthrough an opening |40 in the hand 2, and will be secured by means ofthe screw |4| to the cross bars |01.

In operation, when it is desired to hold an object in the fingers of themechanical hand, the finger control |02 will be moved to connect thelarge cylinder 24 by way of the annular groove 85 in the valve 83 withthe small cylinder 39. The arm is then pumped up and down and hydraulicfiuid from the tank 30 will be pumped under pressure to move the piston9| outwardly in the cylinder 89. This movement will cause the rods and|08 to move outwardly and the finger plates ||1 and |23 to move inwardlyto grasp the -desired article. Upon the movement of the finger control|02 in the opposite direction, the valve 83 will be shifted by means ofthe spring 86 so that the several springs Which were compressed, willforce the hand and fingers to open position and return the hydraulicfiuidvto the tank 30. As before mentioned, the rack bar will determinethe angular position of the forearm portion and may be readily changedby shifting its contact with the pawl or dog 15.

From the foregoing description it will be apparent that there has beendevised and provi-ded a highly efficient and relatively inexpensiveartificial or mechanical hand and interconnected forearm for amputees.

While'the preferred embodiment of the in` stant invention has beenillustrated and described, it will be understood that it is not intendedto limit the scope of the invention thereto, as many minor changes indetail or construction may be resorted to without departure from thespirit of the invention.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent of the United States is:

1. An artificial limb including a forearm portion and a hand portiondetachably connected therewith, a stump supporting cup pivotallyattached to the inner end of said forearm portion, axially disposedcylinders of different sizes in said forearm portion, pistons operablein said cylinders, piston rods attached to said pistons, a hydraulicfluid storage tank in said forearm portion, means for admittinghydraulic fluid from said tank to said cylinders, ratchet operatingmeans connected with one of said piston rods operable upon reciprocatingmovement between said forearm portion and said stump supporting cup,gear connected finger sections supported by said hand, and meansdisposed between said finger sections and the second piston rod foractuating said finger sections when hydraulic fluid is pumped from saidfiuid storage tank into said cylinder.

2. An articial limb including a forearm portionand a hand portiondetachably connected therewith, a stump supporting cup pivotallyattached to the inner end of said forearm portion, axially disposedcylinders of different sizes in said forearm portion, pistons operablein said cylinders, piston rods attached to said pistons, a hydraulicfiuid storage tank in said forearm portion, means for admittinghydraulic fluid from said tank to said cylinders, ratchet operatingmeans connected with one of saidrpiston rods operable upon reciprocatingmovement between said forearm portion and said stump supporting cup,gear connected finger sections supported by said hand, means disposedbetween said finger sections and the second piston rod for actuatingsaid finger sections when hydraulic fluid is pumped from said fluidstorage tank into said cylinders, and a separate means for returningsaid hydraulic fiuid from said cylinders to said fluid storage tank.

3. An .artificial limb including a forearm portion and a hand portiondetachably connected therewith, a stump supporting cup pivotallyattached to the inner end of said forearm portion, axially disposedcylinders of different sizes in said forearm portion, pistons operablein said cylinders, piston rods attached to said pistons, a hydraulicfluid storage tank in said forearm portion, means for admittinghydraulic fluid from said tank to said cylinders, ratchet operatingmeans Iconnected with one of said piston rods operable uponreciprocating movement between said forearm portion of said stumpsupporting cup, gear connected finger sections supported by said hand,means disposed between said nger sections and the second piston rod foractuating said finger sections when hydraulic fluid is pumped from saidfluid storage tank into said cylinders, separate means for returningsaid hydraulic fluid from said cylinders to said fluid storage tank, anda shiftable valve between said cylinders for admitting fluid to operatesaid pistons and for returning the fluid to the fluid storage tank.

4. An artificial limb including a forearm portion and a hand portiondetachably connected therewith, astumpfsupportingcup pivotally attachedto the inner end:- of said, forearm portion, axially disposed cylinders.of different. sizes said. forearm portiQnxpistons; operable in saidcylinders, piston Arods attached to said pistons,y a hydraulic fluidstorage tank; in said forearm portion, means for admitting hydraulicfluid from-said tank tosaid cylinders, ratchetv operating meansconnected with one of said piston rods operable upon reciprocatingmovement between said forearm portion of said stump supporting cup, gearconnected finger sections supported by said hand,.means.disposed betweensaid finger sections and the second pistonrod for actuating said nngervsections when hydrauli fluid is pumped from said fluid storage tank intosaid cylinders separate means for returning said hydraulic fluid from.said cylinders .to` said fluid storage tank, a shiftable valve betweensaid cylinders for admitting fluid to operate said pis.- tons and forreturning the fluid to the fluid storage tank, andresilient means forreturning4 said pistons to their retracted positions in said cylinders.

5. An artificial limb including a forearm pore tion and a hand portiondetachably connected therewith, a stump supporting cup pivotallyattached to the inner end of saidforearm portion, axially disposedcylinders of different sizes in said forearm portion, pistons operablein said cylinders, piston rods attached to said pistons, a hydraulicfluid storage tank in said forearm portion, means for l:admittinghydraulic uid from said tank to said cylinders, ratchet operating meansconnected With one of said piston rods operable upon reciprocatingmovement between said forearm portion of said stump supporting cup, gearconnected finger sections supported by said hand, means disposedbetweensaid finger sections and the second piston rod for actuatingsaid fingersections When hydraulic uid is pumped from said fluid storage tank intosaid cylinders, separate means for returning said hydraulic ud from saidcylinders to said fluid storage'tanky ashiftable valve between saidcylindersfor admitting fluid to .operate said pistons and for returningthe uid to the fluid storage tank, resilient means for returning saidpistons to their, retracted positions in said cylinders, and camactuated means for operating and shifting said shiftable, valve.

6. The subject matter as claimed in claim 5, and resilient means forreturning said shiftable valve toits originaly position.

'71, The subject matter as claimed in claim 5, resilient means forreturning said shiftable valve to its original position, and adjustablemeans for varying the kangular relation between said forearm portion andsaid stump supporting cup.

8,. The subject matter as claimed in claim 5, a thumb pivotallysupported on said hand por-Y tion, and actuating means thereforconnected with said nger actuating means.

9-. The subjectmatter as claimed in claim 5, a thumb pir/Totallysupported on said hand portion, actuating means therefor connected withsaid finger actuating means, and finger tip control links` pivotallyconnected between said hand portion and said fingers.

10. The subject matter as claimed in claim 5 a thumb pivotally supportedon said hand portion, actuating means therefor connected with saidfinger actuating means, finger tip control links pivotally connectedbetween said hand portion and said fingersl and resiliently cushionedconnecting members between said ngers and saidl finger actuating means.

l1. The subject matter as claimed in claim l, and a clamp engageablewith said hand portion and forearm portion for securing the sametogether. v

12. The subject matter as claimed in claim 2, and means for engaging anddisengaging said ratchet operating means.

THOMAS C'. HARRY.

No references cited.

